title: A 4 K cryogenic probe for use in magnetic resonance force microscopy experiments.
abstract: The detailed design of a mechanically detected nuclear magnetic resonance probe using the SPAM (Springiness Preservation by Aligning Magnetization) geometry, operating at 4 K, in vacuum, and a several-Tesla magnetic field is described. The probe head is vibration-isolated well enough from the environment by a three-spring suspension system that the cantilever achieves thermal equilibrium with the environment without the aid of eddy current damping. The probe uses an ultra-soft Si cantilever with a Ni sphere attached to its tip, and magnetic resonance is registered as a change in the resonant frequency of the driven cantilever. The RF system uses frequency sweeps for adiabatic rapid passage using a 500 μm diameter RF coil wound around a sapphire rod. The RF coil and optical fiber of the interferometer used to sense the cantilever's position are both located with respect to the cantilever using a Garbini micropositioner, and the sample stage is mounted on an Attocube nanopositioner.
authors.affiliation: U.S. Army Research Laboratory, 2800 Powder Mill Road, Adelphi, Maryland 20783, USA.
authors.forename: Doran D
authors.initials: DD
authors.lastname: Smith
authors.forename: Dimitri A
authors.initials: DA
authors.lastname: Alexson
authors.forename: Joseph L
authors.initials: JL
authors.lastname: Garbini